IB Sports, exercise and health science A.3.3.4 Hydration and Nutritional Strategies for Exercise Recovery Notes

Nutrition and Recovery

1. Recovery from training and competition depends heavily on what an athlete consumes after exercise, since post-exercise nutrition restores depleted fuel stores, supports tissue repair, and re-establishes fluid and electrolyte balance.
2. Nutritional planning must address both quantitative needs (total energy intake) and qualitative needs (the composition of macronutrients and micronutrients).
3. An athlete who consumes adequate calories but the wrong mix of nutrients will recover incompletely.

Macronutrient Intake for Recovery

1. Carbohydrates

1. Carbohydrates are the primary fuel source for the body, stored as glycogen in muscles and the liver.
2. Post-exercise carbohydrate intake is crucial for restoring glycogen levels and ensuring energy availability for future activity.
3. Glycogen resynthesis is the process of replenishing glycogen stores after exercise to restore energy balance.

Factors Affecting Glycogen Resynthesis

1. The first 2 hours after exercise is the critical window for glycogen replenishment, when muscle is most sensitive to carbohydrate availability.
2. Glycemic Index (GI): High-GI foods (e.g., white rice, bananas) promote faster glycogen recovery, while low-GI foods (e.g., oats, lentils) provide sustained energy.

Carbohydrate Quantification

1. The minimum intake rate to support glycogen replenishment is 0.7 g per kg of body mass per hour.
2. After prolonged intense exercise, full restoration of glycogen stores requires a daily intake of 8 to 12 g per kg per day.
3. Complete glycogen resynthesis typically takes about 24 hours when intake is adequate.
4. Foods with a high glycaemic index raise blood glucose quickly and accelerate glycogen resynthesis compared with low-glycaemic-index foods.
5. Carbohydrate drinks are advantageous because they contribute to rehydration at the same time as fuel replacement.

2. Proteins

1. Protein is essential for muscle repair, growth, and adaptation.
2. Exercise causes microtears in muscle fibers, which require protein for recovery.

Optimal Protein Intake for Recovery

1. Approximately 20 g of protein at a single feeding maximises muscle protein synthesis, and larger amounts at one sitting confer little additional benefit.
2. Complete proteins (e.g., whey, eggs, chicken) contain all essential amino acids needed for muscle repair.

Animal vs Plant Sources

1. Animal-based protein sources stimulate higher rates of muscle protein synthesis than plant-based sources.
2. The difference is attributed to the amino acid profile, particularly the leucine content, and to the rate at which the protein is digested and absorbed.
3. Athletes following plant-based diets can still meet protein requirements but may need higher total intakes or combinations of sources to match the response produced by animal protein.

3. Fats

Fats play a role in long-term recovery and inflammation control.